Firstly I would like to say I’m privileged to have access to the forum. I’m a PhD student. My research is focused on aerodynamics of wind turbine, At the moment I’m trying to build CAD model of the NREL 5MW baseline rotor so I can make a GRID and undertake a CFD analysis, but having some difficulties with the geometric definition that are available regarding the NREL 5MW rotor. I’ll give a summary what I have gathered so far.
The geometry of the NREL 5MW blade is based on the LMH64-H blade (reduced rotor and hub diameter) , which was initially used on the DOWEC 6MW rotor. Unfortunately I have been unsuccessful in obtaining the geometric definition of LMH64-5 blade, except the DOWEC paper . In the NREL 5MW document the airfoils are given are in an abbreviated form, but using the DOWEC document , the airfoil names used on the LMH64-5 blade can be obtained with some confusions. Here is what I have decrypted from comparing NREL and DOWEC publications.
DU40_17 = DU 99 W 405 LM
DU35_A17 = DU 99 W 350
DU30_A17 = DU 97 W 300 LM
DU25_A17 = DU 91 W2-250
DU21_A17 = DU 93-W-210 LM
NACA64_A17 = NACA 64-618
Is this Correct?
LM indicates original blade with a reduced trailing edge thickness i.e. DU 99 W 405 LM is the DU 99 W 405 airfoil with smaller trailing edge thickness. ‘_A17’ indicate that the blade section has an aspect ratio of 17.
TU Delft have informed me that all the airfoils used in the LMH64-5 DOWEC blade are ‘probably’ the LM profiles. There is also another uncertainty that arises in the airfoil sections, the DU airfoils particularly DU 99 W 405 LM & DU 99 W 350 LM has an adjusted form(see atached image). Hence I’m not entirely sure which airfoil section the NREL have used for their 5MW baseline rotor.
Lastly from the NREL document , I was able to obtain the axial position on the airfoil section where the pitch axis passes through (AeroCent-0.25). But the information regarding the tangential position on the airfoil, where the pitch axis passes through is not available especially that fact that LMH64-5 is a prebend blade, therefore this information is vital to create an accurate geometry of the blade.
Could anyone please help to with my question regarding the exact airfoil sections used and how they are stacked along the NREL 5MW rotor blade?
Any help is greatly appreciated.
Thanks in advance.
P.S. I have written a lot because i thought it will help others who may be doing something similar to me, hope this is ok.
H Jonkman J, Butterfield S, Musial W, Scott G. Definition of a 5-MW reference wind turbine for offshore system
development. Technical Report NREL/TP-500-38060, National Renewable Energy Laboratory, Golden, CO, 2009.
Kooijman, H. J. T., Lindenburg, C., Winkelaar, D., and van der Hooft, E. L., “DOWEC 6 MW Pre-Design: Aero-elastic modeling of the DOWEC 6 MW pre-design in PHATAS,” DOWEC Dutch Offshore Wind Energy Converter 1997–2003 Public Reports [CD-ROM], DOWEC 10046_009, ECN-CX–01-135, Petten, the Netherlands: Energy Research Center of the Netherlands, September 2003…J.T.